1. Field of the Invention
The present invention relates to a floating type brake disk assembly which is used for braking vehicles or the like and which can be thermally expanded freely when a disc is heated to a high temperature due to a friction heat at the time of braking.
2. Description of Related Art
A conventional hollow pin to be used for connecting a disc to a hub in a manner slightly displaceable relative to each other in the axial direction has the construction as shown in Japanese Published Unexamined Utility Model Registration Application 40347/1989. The construction is as shown in FIG. 11 in which reference mark "a" denotes a hub, b denotes a disc and c denotes a pin. The pin c has a flange d, a stepped portion e and a small-diameter portion f. After the pin c has been inserted into a pair of connecting dents or recesses which are provided in a connecting portion g of the hub "a" and the disc b, a coned disc spring h and a fixing washer i are fitted onto the small-diameter portion f. The coned disc spring h is held via the fixing washer i by a caulked portion f' which is formed by caulking an end of the small-diameter portion. Both side surfaces of the hub "a" and of the disc b are thus held in a pinching manner by the coned disc spring h and the flange d. A torque is transmitted by the pin c and the clattering in the axial direction is prevented by the coned disc spring h.
As the coned disc spring h, there are two types as described in the above-described Japanese Utility Model Registration Application. One of them is as shown in FIG. 12(a). The same or substantially the same parts are affixed with the same marks as used hereinabove. The coned disc spring h is of a simple truncated cone and is inserted or placed into the dents which extend over the hub "a" and the annular disc b. The coned disc spring h is further fitted onto a pin j having a stepped portion j.sub.1 and a small-diameter portion j.sub.2 and is urged or pressed by a washer i which is held in position on the stepped portion j.sub.1 by caulking.
However, this type of construction has the following disadvantage as shown in FIG. 12(b). Namely, the coned disc spring h is likely to be deviated or moved off the center at the time of assembling, and is therefore stepped onto the stepped portion j.sub.1. If the pin j is caulked in this condition, as shown in FIG. 12(c), the coned disc spring h may contact the hub "a" but not the disc b and, consequently, elasticity cannot be worked or operated on the disc b.
The other type of coned disc spring k is provided, as shown in FIG. 13, with a bottom portion (or a top portion as seen in Figure) k.sub.1 having a central hole. The central hole is fitted into the small-diameter portion j.sub.2 of the pin j. According to this construction, there is no possibility that the coned disc spring k may deviate at the time of assembling. However, the portion k.sub.2 in the periphery of the bottom portion is subjected to repeated bending and there is, therefore, a disadvantage in that this portion k.sub.2 is likely to be fatigued.
The above-described brake disc assembly employs, aside from the hub "a" and the disk portion b, three more parts of a pin c, j, a coned disc spring h, k and a fixing washer i. Since many pins are used in one brake disc assembly, the number of associated coned disc springs h, k and fixing washers i becomes large. As a result, the costs of parts and assembling will inevitably become expensive.
In view of the above disadvantages, the present invention has an object of providing a floating type brake disc assembly that enables to decrease the number of parts. The present invention also has another object of providing a floating type brake disc assembly in which it is easy to set springs such as coned disc springs in a right position at the time of assembling, thereby enabling to apply a right set load, and in which the set load does not vary.
According to one aspect of the present invention, there is provided a floating type brake disc assembly which comprises: a hub; an annular disc which is concentrically disposed around the hub, the hub and the disc having plural sets of connecting dents each set of which is opposingly provided in a connecting portion of the hub and the disc; a hollow pin which has a flange on one end thereof and is inserted into each set of the connecting dents such that the hub and the disc are connected together while allowing for a slight floating movement therebetween. The hollow pin has a thick-wall tube portion which lies next to the flange and is adapted to be inserted into each of the connecting dents and a thin-wall tube portion which has an outer diameter smaller than that of the thick-wall tube portion and is provided next to the thick-wall tube portion away from the flange. The thin-wall tube portion is caulked with its outer periphery bending towards one side surface of the connecting portion to form a caulked flange such that the outer periphery holds the above-described one side surface of the connecting portion.
According to another aspect of the present invention, there is provided a floating type brake disc assembly which comprises: a hub; an annular disc which is disposed around the hub, the hub and the annular disc having plural sets of connecting dents; a pin which has a shaft portion on one side along the pin and a flange provided on one end of the shaft portion, the pin being adapted to be inserted into each set of the connecting dents; and a coned disc spring and a washer which are mounted on an opposite end of the shaft portion. The hub and the disc are thus held together in a pinched manner, when assembled, by the flange, the coned disc spring and the washer. The length of the shaft portion is set larger than a sum of a thickness of the hub or the disc and a height of the coned disc spring under no-load condition. The washer has an annular projection projecting towards the coned disc spring. The inner diameter of the annular projection is larger than an outer diameter of the shaft portion. The washer is fixedly seated, when assembled, onto an axially outer end of the opposite end of the shaft portion such that the annular projection presses the coned disc spring.
According to still another aspect of the present invention, there is provided a floating type brake disc assembly which comprises: a hub; an annular disc which is disposed around the hub, the hub and the disc having plural sets of connecting dents; a pin which has a shaft portion on one side along the pin and a flange provided on one end of the shaft portion, the pin being adapted to be inserted into each set of the connecting dents; a washer which is fixed to that end of the pin which is away from the flange; a spring which pressingly contacts a side surface of the hub and the disc, respectively, thereby holding, when assembled, the hub and the disc in a pinching manner by the flange, the washer and the spring; wherein the spring is disposed on the side of the flange of the pin.
According to the above-described one aspect of the present invention, the thin-wall tube portion on one end of the hollow pin is easily deformed at the time of caulking into a disc-like flange. This deforming does not substantially extend to or affect the thick-wall tube portion. Therefore, the thick-wall tube portion can be maintained in the shape and dimensions which correspond to the connecting dents. The flange obtained by caulking the thin-wall tube portion directly or indirectly abuts one side surface of the connecting portion of the hub and the disc. A lateral deviation or movement of the hub and the disk relative to each other is therefore prevented.
According to the above-described another aspect of the present invention, when the coned disc spring is fitted onto the pin at the time of assembling, since the upper or the inner end of the coned disc spring is positioned axially inward of the stepped portion or does not axially protrude beyond the stepped portion, the coned disc spring will not deviate or move in its position. Therefore, after the washer has been caulked, a predetermined set load is generated by the push with the annular projection.
According to still another aspect of the present invention, the deviation of the spring is prevented by the pin. The wear on the side surfaces of the hub and the disc by the spring can be prevented by a protection washer. Therefore, the amount of compression of the spring does not vary and consequently the variation in the set load can be prevented.